Lithium batteries have been widely used as power sources for electronic devices whose temperature range for use is set to about −20 to 60° C. based on the temperature range of living environment of human. Meanwhile, the application range of electronic devices using batteries as power sources has been growing recently, and along with that, the temperature range for use of electronic devices has also been growing. For example, batteries used for on-vehicle electronic devices are required to maintain their function for a certain period of time even in a high ambient temperature of about 125° C., and they are also required to operate even at a low temperature of about −40° C.
As batteries suitable for uses in such a high temperature environment, lithium primary batteries using manganese-containing oxides such as manganese dioxide or fluorinated graphite in the positive electrode and using lithium or lithium alloys in the negative electrode have good prospects. However, in a high temperature environment, a solvent of the electrolyte reacts with the positive electrode to decompose, thereby generating gas. In particular, since manganese-containing oxides (may be referred to as “manganese oxides” simply, hereinafter) such as manganese dioxide exhibit catalytic action against the solvent of the electrolyte, the decomposition reaction of the electrolyte becomes notable by using manganese oxides in the positive electrode. Especially, in a high temperature region exceeding 100° C., the electrolyte is decomposed more easily, and generated gas may increase internal pressure of the battery. In coin-type batteries, the increase in the internal pressure of the batteries may possibly impair contact between parts inside the batteries, which leads to a reduction in the pulse discharge characteristics due to an increase in the internal resistance of the batteries. Further, there are also possibilities of electrolyte leakage, breakdown, and explosion of the batteries, which may give damages to electronic devices. Also, in cylindrical batteries having a current collecting structure by leads, electrolyte leakage may be caused by an increase in the internal resistance of the batteries, which may lower battery characteristics.
Meanwhile, Patent Literatures 1 to 4 propose a method for adding cyclic sultone derivatives, acid anhydrides and the like to the electrolyte in order to suppress generation of gas in such a high temperature region.
Also, Patent Literature 5 proposes a method for suppressing generation of gas in the high temperature environment by reforming manganese oxide.